412 Mr. R. Kidston on the Fructification and 



LIV. — On the Fructification and Affinities of Archseopteris 

 liibernica, Forbes, sp. By Egbert Kidston^ F.R.S.E., 

 F.G.S.* 



Under the name of Cyclopteris hihernica, Archceopteris 

 hibernica was described by Forbes in 1852 f from the Yellow 

 Sandstones of the south of Ireland, where, at Kiltorkan and 

 a few other localities, this fern is one of the most character- 

 istic fossils. 



In 1858 X Mr. W. H. Baily, in describing the fructification 

 of Arch(eo2)teris hibernica, Forbes, sp., said that " one of the 

 fertile pinnules of a specimen showed the spores were aggre- 

 gated into clusters or sori, and that the indusium or protecting 

 cover had been but little broken up. A fertile pinnule from 

 another specimeuj however, appeared to be in a more ad- 

 vanced stage, losing in a great measure the aggregated 

 character of the sori, and showing the protecting cases (which 

 were granulated) to be much disturbed. 



" Other specimens in the collection were alluded to, one of 

 which, with a length of 16 inches, had twelve pinnules on 

 each side of the rachis in full fructification without any 

 appearance of leaflets, the spore-cases being scattered in all 

 directions ; another of the same length had about twenty 

 pinnules on each side, the lower ones being in full fructifica- 

 tion, which decreased gradually towards the upper portion of 

 the frond, the leaflets taking its place." 



At the same time Mr. Baily exhibited a diagram illus- 

 trating " what was considered to be the base of the stem or 

 rhizonia, having a rounded expansion, apparently separating 

 into scales which continued upwards, tragments of leaflets 

 being attached to the stem at different intervals." 



Schimper, in 1869 §, figured and described Cyclopteris 

 hibernica, Forbes, under the name of Paheopteris hibernica. 

 In describing the fruiting pinnules he says : " These 

 have undergone a complete metamorphosis and are trans- 

 formed into groups in which all foliar expansion has entirely 

 disappeared, and which show a principal rachis not at all 

 represented in the sterile pinnules which are destitute of a 

 medial nerve." He also describes the sporangia as clavate, 



* Communicated by the Author, having been read before the Royal 

 Physical Society of Edinburgh, April 18, 1888. 

 t Brit. Assoc. Report, 1852, p. 43. 

 t Ihid. ]858, p. 75. 

 § Traite d. pal^ont. veget. vol. i. p. 475, pi. xxxvi. 



